Certain medical procedures involve the injection of a pharmaceutically active agent at a plurality of positions on a patient's skin. These procedures often employ a template to mark the injection sites on the patient's skin with a removable tattoo. However, such templates do not distinguish one injection site from another. As a result, some injection sites may be over- or under-dosed as a result of human error. Therefore, a need exists for marking a patient's skin in a unique manner such that a physician can readily remember and identify sites that have been or have not been injected with a pharmaceutically active agent. Such a template would reduce human error and reduce and/or prevent over- or under-dosing at an injection site.